It should be fairly easy to change your major. Especially because of the extensive course overlap between CSE and CS.
You’ll probably have to take just a couple of extra/different courses. Rest all the courses will be same. Hence, the university should not object.
A possible case in which you may not be allowed to change is if CS specific classes are full and there is no space.
If you want, you can always shoot an email to the university asking about the change. It is possible that they’ll just guide you through a simple form that you may fill up and it’s done 